Taiwanese Patent Application Publication No. 402123“The keyboard device with expandable function keys (Continuation 1)” describes that “a type of keyboard device with expandable function keys (Continuation 1), comprises a keyboard and multiple expandable function keys on the keyboard. The function keys need to be connected to additional Input/Output signal lines of the microprocessor circuit inside the keyboard. These additional Input/Output signal lines are to be combined with the original key matrix of the keyboard to create a new key matrix, which will encode the function keys in such a way that the key codes can be recognized by the Windows application software. A user can use a keyboard to directly control the features of peripheral devices and to know the controlling result from a displaying screen.” In order to expand the number of function keys, the prior art needs additional Input/Output lines connected to the microprocessor circuit. The prior art clearly increases the cost of the keyboard.
In order to overcome the disadvantage of the prior art, the inventor of the present invention invents a keyboard and a key constructing method, which completely overcomes the disadvantage of the prior art. The present invention can expand the number of keys on a keyboard without increasing the number of scan/return lines. The expanded keys generated can be used as hot keys.